I used BBM when I had a Blackberry Pearl. I have no idea why it's awesome, or why I liked it. To be honest it's not that different than BeeJive or the many IM applications in the App Store that support Push. I think part of the popularity of the program is the exclusivity of it. I guess it's like you're in a secret club. One nice thing about it, is the ability to see if they read the message you sent.
I have a feeling that feature could be implemented in any number of the current offerings in the App Store.
I have a feeling that feature could be implemented in any number of the current offerings in the App Store.